题型:阅读理解 题类:常考题 难易度:普通
四川省射洪县射洪中学2019届高三上学期英语开学考试(应届)试卷
In cooperation with German experts, several scientists from the University of Bradford believe that they finally solved a mystery that has been confusing millions of people: why our hair turns gray with age.
The researchers came up with their results by examining native hair and cells from human hair follicles(毛囊). They say the secret turns out to be hidden in catalase(过氧化氢酶), which is causing hair to turn gray.
Catalase production goes down with age and stress, allowing hydrogen peroxide(过氧化氢) in the hair to do its favorite job—making hair gray, and then white, by blocking the normal production of melanin(黑色素). Melanin is our hair's natural pigment that is responsible for the color of hair. It also determines the color of our eyes and skin.
Dr. Gerald Weizmann, an editor of a journal, says," All of our hair cells make a tiny bit of hydrogen peroxide, but as we get older, this little bit becomes quite a lot, and our hair turns gray and then white."
The new study brings hope for millions of people who have to color their hair: to finally obtain some shampoo that will decrease levels of hydrogen peroxide and therefore restore gray or white hair to its natural color or even prevent it from turning gray.
The researchers are already conducting an experiment with such a drug on a few volunteers with gray hair and expect to get the results in the next two to three months. If everything works out, millions of people will choose between this drug and other previously used expensive dyes. However, even if the drug works, it will take at least several years before it can be brought to the market.
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